Overclocking The Athlon II X3 435
For about $120, the Phenom II X3 720 BE provides two things that the Athlon II X3 435 does not: 6MB of L3 cache and an unlocked CPU multiplier. Now, while an unlocked multiplier certainly can make overclocking a lot easier, it doesn't necessarily provide better results. In our experience, most Phenom II X3 720 CPUs should be able to make it to the 3.7 GHz neighborhood easily. Some folks will make it over 4 GHz with a bit of effort, but other Phenom II X3 720 samples won't be as accommodating.
Since we're comparing the new Athlon II X3 435 to its Phenom II X3 720 BE cousin on a value basis, we wanted to see how far the 435 could stretch its overclocking legs. With a nice, high 14.5 clock multiplier, the new Athlon II X3 435 is a prime candidate for overclocking. Now, we're not looking for a monster overclock here, but we'd like to see what the CPU is willing to provide without too much trouble or to much heat.
Helping out in this respect is a formidable ZEROtherm Nirvana NV120 cooler. Though it's admittedly more cooler than most enthusiasts will employ with an Athlon II X3 435, it will be useful to see how far the CPU can go without heat being too much of a problem. We'll also have a chance to see how well Asus' M4A785TD-V EVO motherboard works when pushed a little.
Upping the CPU to 1.525V in the BIOS, we set the chip's reference clock to 270 MHz for a 3,915 MHz clock speed. While we were able to boot at this setting, the system was somewhat unstable during Prime95 stress testing. As our goal was to see what this CPU could do on a 24/7 basis without pushing it too far, we weren't willing to throttle up the voltage any further, so we backed down until things got stable.
At the end of the day, we settled on a 260 MHz CPU reference clock for a resulting 3,770 MHz clock. We also lowered the HyperTransport multiplier to eight (listed as 1,600 MHz in the BIOS) for an overclocked 2,080 MHz HT speed. Memory was set to 533 MHz in the BIOS, resulting in a 693 MHz (1,386 MHz DDR) clock, and memory latencies were manually set to 9-10-10-25-34 for stability.
This is a respectable overclock for an $87 CPU, and with a Prime95 load temperature of just under 50 degrees Celsius (likely thanks in no small part to the NV120 cooler) we're quite confident in long-term 24/7 prospects for this configuration. We benchmarked the Athlon II X3 435 at both stock and overclocked settings in order to demonstrate the overclocking advantage.
